AIRWAYS COMMUNICATION SERVICE 801 



writer may type a message which will appear on the tape fed auto- 

 matically from the apparatus at every other connected point. The 

 message is automatically and permanently recorded under the control 

 of the sending station. Constant attendance or listening-in is, there- 

 fore, not required; and operators at the various receiving points are 

 thus free to attend to telephone calls from intermediate fields, to 

 operate radio beacons and lights, and to carry on whatever duties 

 may be assigned to them. 



Telephone-typewriter service has been initiated by the Department 

 of Commerce at Hadley Field, at Cleveland, at Chicago and at San 

 Francisco, where in each place the local radio stations, weather bureau 

 offices and the airport offices are all interconnected. It is planned, 

 at a later date, to equip experimentally some airway with complete 

 telephone-typewriter service between airports. 



When an aviator leaves an airport he should be given information 

 of the weather along the route ahead of him and a forecast of the nature 

 of probable changes during the time of his flight. If general weather 

 conditions are settled, or if his flight is a short one, a forecast is entirely 

 adequate. However, for long flights and at times of uncertain and 

 threatening weather, it is important that the pilot be continuously 

 advised by radio of the weather conditions he may encounter during 

 his flight. In particular, reports of the visibility and landing condi- 

 tions at the airport where he expects to land and storm warnings should 

 be sent him. Weather and landing advice can be broadcast from 

 each airport along the airway. Provision of radio transmitters at 

 airports and receiving sets in the planes will make possible a simple 

 one-way system of communication and will permit any number of 

 planes in the air to be advised without confusion. 



The Department of Commerce, in its program of Aids for Air 

 Navigation plans to install radio-telephone transmitters at principal 

 terminal fields to broadcast, to planes in flight, weather and landing 

 information. In addition, there will be a radio-beacon service to 

 assist pilots in finding the landing field. 



European practice, however, has not developed a broadcasting 

 service along this line but has evolved a two-way system in which 

 the pilot of the airplane talks with the nearest airport. Such a system 

 has obvious advantages where it is desired by an air transport company 

 to instruct or control rather than merely inform its aviators. The 

 obvious disadvantage lies in the fact that on a single radio channel 

 the airport can converse with only a single airplane at a time. On 

 the London-Paris airway, it is reported, the practice has recently been 

 adopted of communicating on one channel by radio telegraph with the 



